Using the Spectral characteristics of gold nanorods to investigate heavy metals Pb in agricultural soils. Studied included: (1) The effects of humic acid on Pb transformation and its formation changing were explored. The laboratory model was established to simulate Pb leaching process in the soil and investigated the change of total Pb content at different layers. (2) The migration and transformation of different forms Pb were studied by the nano system. The effect of humic acid and pH were analyzed based on the nano-analysis method. (3) The relationship between various forms Pb irons were analyzed. (4) The data showed that ion exchange state and iron-manganese oxidation state Pb were more likely to enriched at 0 cm depth, and organic bound state was more likely to enriched at 10 cm depth. Humic acid increased the solidify ability of different forms of Pb in agricultural soil, and the analysis system was efficient to supply the exactly transition process.

Use of elemental mercury (Hg⁰) to enhance placer gold recovery is an effective method dating back centuries, but is associated with significant atmospheric Hg⁰ losses. This method was widely used in the Canadian Klondike region during most of the 20th century when the mining industry experienced rapid growth. While the health risks associated with Hg⁰ pollution are now well understood, few studies have assessed the environmental legacy of Hg⁰ use in the Klondike. We used an annually resolved Picea glauca tree-ring Hg record (1864–2015) to reconstruct and evaluate changes in local atmospheric Hg⁰ concentrations associated with gold production at the Bear Creek mining camp. Major temporal trends in the record are consistent with the scale of Bear Creek operations and are distinct from background trends at an unimpacted control site. Tree-ring Hg concentration increased most rapidly from 1923 to 1930, a period when several major mining operations were consolidated at Bear Creek. The highest Hg concentrations, ∼2.5× greater than pre-mining era, occurred in the 1930s, coinciding with maximum gold production at this site. Post-World War II economic factors adversely affected the industry, causing declining tree-ring Hg concentrations from 1939 to 1966. Closure of the Bear Creek camp in 1966 coincided with the strongest tree-ring Hg decline, although a return to background levels did not occur until the 1990s, likely due to re-emission of legacy Hg⁰ from contaminated soils. Finally, a robust increase was observed over the last decade, similar to other tree-ring Hg records in N.W. Canada, which is linked to rising Hg⁰ emissions in Asia. The Bear Creek tree-ring Hg record provides a unique opportunity to study the impact of Klondike gold mining on the local environment at annual resolution and demonstrates great potential to use Picea tree rings to study past changes in atmospheric Hg⁰ from local and global emissions.A 151-year long, annually resolved tree-ring Hg record was developed at a historic Klondike gold-mining site to investigate the influence of mining-related Hg⁰ emissions on the local atmosphere and environment. Compared to a control site, the tree-ring Hg record documents highly elevated atmospheric Hg⁰ concentrations during the period mining activities were ongoing at this site.

This study determined the contamination levels of oil and grease (O/G) across nine (9) galamsey operations under different environmental media (background soil, surface drainage, slurry/sludge and galamsey wastes) in three galamsey hotspot assemblies (Tarkwa Nsuaem, Amenfi East and Prestea Huni Valley) within the Western region of Ghana. Triplicate samples each of the four environmental media for the nine galamsey types (Washing Board, Washing Plant, Anwona, Dig and Wash, Dredging, Underground Abandoned Shaft, Underground Sample Pit, Chamfi and Mill House) were collected and analysed using n-hexane extractable materials in acidic medium by extraction and gravimetry to determine O/G concentrations. From the comparison of mean ranked concentration of O/G, using Kruskal-Wallis Test, the observed differences in the ranking was significant across all four media. The O/G concentrations for Anwona, Chamfi, Mill House, Washing Board and Washing Plant galamsey recorded exceedances when compared to the Ghana EPA Effluent Guideline Value of 100 mg/L for water and The New Dutch Lists’ Target and Intervention Value of 50 mg/kg and 500 mg/kg for solid/semi-solid materials. Consistently and for all environmental media types, the levels of O/G across the galamsey types were in the descending order of: Washing Board, Chamfi, Anwona, Mill House, Washing Plant, Underground Sample Pit, River Dredging, Dig and Wash, Underground Abandoned Shaft and Control Sample (non-galamseyed areas). In general, the surface drainage medium was predominantly found to be the most impacted upon medium from hydrocarbons by seven of the nine galamsey operations (Washing Board, Anwona, Chamfi, Mill House, Dredging, Dig and Wash and Underground Sample Pit). This was followed by slurry/sludge, background soil and waste media in that order. Expectedly, there were no exceedances for the Reference or Control Samples (non-galamseyed areas).

Nicotine (Nic) exposed to the environment which comes from tobacco products is the main addictive agent and specific classes of hazardous compound that merit concern. In this study, we have established a fast and reliable method to achieve specific detection of Nic in natural nicotiana tabacum within 30 s through a miniaturized platform based on screen printed gold electrode (SPE). A simple electrochemical pretreatment mean was employed on gold surface that led to the exposure of Au (111) facet and a convenient sample pretreatment method was adopted to realize the extraction of Nic in tobacco. The present electrochemical sensor exhibits an ample range of sensing from 10 μg/g to 200 μg/g, which is able to compliance with tobacco industry testing standards of actual samples. Over 60 sampling points from different origins in China or other countries were performed with direct analysis using this method and satisfactory results have been obtained. The proposed approach was demonstrated to be a very promising platform for significantly improving analytical efficiency in laboratories as well as for monitoring the source reduction control of Nic in the environment.

This study describes the development of a sequential extraction procedure for the evaluation of metal nanoparticle mobility and bioaccessibility in soils. The procedure, that was developed using gold nanoparticles (AuNPs) as model species, relies on the fractionation of nanoparticles by sequentially dissolving soil matrix components (carbonates, metal oxides, organic matter and mineral phases) in order to release the entrapped nanoparticle species in the extract solution. By summing up the concentration of AuNPs recovered in each fraction it was found that 93.5% of the spiked AuNP concentration could be recovered which satisfactorily represents the nominal AuNP concentration in the soil. The efficiency of the procedure was found to depend on several procedural artifacts related to the separation of AuNPs from soil colloids and the reactivity of the extraction reagents with AuNPs and their precursor metal ions. Based on the results obtained a protocol for the speciation of the AuNPs and Au ions in the soil sample was also developed. The results of the study show that both AuNPs and Au ions are mainly associated with soil organic matter, which significantly reduces their mobility, while a small amount (<10%) is associated with metal oxides which are more mobile and potentially bioaccessible. The developed procedure provides a springboard for further development of sequential extraction procedures of metal nanoparticles in soils that could be used to assess both the exposure and release of metal nanoparticles and their precursor metal ions in the environment (as total extractable concentration) as well as provide evidence regarding their bioaccessibility and potential bioavailability by determining the concentration of nanoparticles in each specific soil fraction.

Trace elements and Hg isotopic composition were investigated in mineralized rocks, barren rocks, and mineral soils in the Xianfeng prospect, a shallow buried epithermal gold deposit in northeastern China, to understand whether this deposit has left a diagnostic geochemical fingerprint to its weathered horizon. All the rocks and soils display congruent patterns for immobile elements (large ion lithophile elements, high field strength elements, and rare earth elements), which reflect the subduction-related tectonic setting. Both mineralized rocks and soils showed common enrichment of elemental suite As–Ag–Sb–Hg, suggesting that the Xianfeng gold deposit has released these elements into its weathered horizon. Similar mercury isotopic composition was observed between mineralized rocks (δ²⁰²Hg: −0.21 ± 0.70‰; Δ¹⁹⁹Hg: −0.02 ± 0.12‰; 2SD) and barren rocks (δ²⁰²Hg: −0.46 ± 0.48‰; Δ¹⁹⁹Hg: 0.00 ± 0.10‰; 2SD), suggesting that mercury in the Xianfeng deposit is mainly derived from the magmatic rocks. Mineralized soils (δ²⁰²Hg: −0.44 ± 0.60‰; −0.03 ± 0.14‰; 2SD) and barren soils (δ²⁰²Hg: −0.54 ± 0.68‰; Δ¹⁹⁹Hg: −0.05 ± 0.14‰; 2SD) displayed congruent Hg isotopic signals to the underlying rocks, suggesting limited Hg isotope fractionation during the release of Hg from ore deposit to soils via weathering. This study reveals evidence of a simple and direct geochemical link between this shallow buried hydrothermal deposit and its weathered horizon, and highlights that the weathering of shallow-buried hydrothermal gold deposits can release a substantial amount of heavy metals (e.g. Hg, As and Sb) to surface soil.

The contributions of contaminant sources are difficult to resolve in the sediment record using concentration gradients and flux reconstruction alone. In this study, we demonstrate that source partitioning using lead isotopes provide complementary and unique information to concentration gradients to evaluate point-source releases, transport, and recovery of metal mining pollution in the environment. We analyzed eight sediment cores, collected within 24 km of two gold mines, for Pb stable isotopes, Pb concentration, and sediment chronology. Stable Pb isotope ratios (²⁰⁶Pb/²⁰⁷Pb, ²⁰⁸Pb/²⁰⁴Pb) of mining ore were different from those of background (pre-disturbance) sediment, allowing the use of a quantitative mixing model. As previously reported for some Arctic lakes, Pb isotope ratios indicated negligible aerosol inputs to sediment from regional or long-range pollution sources, possibly related to low annual precipitation. Maximum recorded Pb flux at each site reached up to 63 mg m⁻² yr⁻¹ in the period corresponding to early years of mining when pollution mitigation measures were at a minimum (1950s–1960s). The maximum contribution of mining-derived Pb to these fluxes declined with distance from the mines from 92 ± 8% to 8 ± 4% at the farthest site. Mining-derived Pb was still present at the sediment surface within 9 km of Giant Mine more than ten years after mine closure (5–26 km, 95% confidence interval) and model estimates suggest it could be present for another ∼50–100 years. These results highlight the persistence of Pb pollution in freshwater sediment and the usefulness of Pb stable isotopes to quantify spatial and temporal trends of contamination from mining pollution, particularly as concentrations approach background.

In order to evaluate the effect of mining activity on the environment of the Qhorveh mining area in the west of Iran, the geological, ecological and environmental data, related to social development and regional economic status, were used. The geological data included seven sub-indices, such as vegetation coverage, land utilization type, and fault activity; ecological data, with two sub-indices, such as degree of ecological environment recovery; and finally, environmental data, with three sub-indices, such as soil and dust pollutions. These were selected based on the literature and expert opinion which were utilized for environmental pollution and geo-ecological (EPGE) risk assessment of the study site. Remote sensing (RS) image, field sampling, digital elevation map, and data retrieved from different government agencies were used to generate layers for the sub-indices in the geographic information system (GIS) environment. In addition, the analytical hierarchy process (AHP) method was used to determine the weight of sub-indices. Five levels consisting of best, good, middle, poor and worst were used to describe the EPGE risk assessment of the Qhorveh mining area. Results showed that worst and poor levels of EPGE risk are in the east and northeast of the study area where the gold and pumice mines are located while best and good levels of EPGE risk are in its center where the stone mines are located. According to the results of this research, the EPGE risk assessment of the Qhorveh mining area is affected by the environmental pollution index with its highest weight (0.3908). It can be concluded that the integration of the RS, GIS and AHP methods proposed in this study improved the evaluation quality of EPGE risk assessment.

Herein, we demonstrate a nanocomposite material Eu/ZnO/pPy for enhanced performance in photoelectrocatalytic degradation of chemical warfare agent sulphur mustard (SM) at ambient conditions which is growing concern of the Scientific Community amidst the current climate of terrorism. Eu/ZnO/pPy was electrochemically prepared on Au electrode at ambient conditions and was used for electrocatalytic reductive elimination of chloride from SM and results indicated one electron involvement process for the cleavage of the carbon-chloride bond. Surface morphology of Eu/pPy, ZnO/pPy and Eu/ZnO/pPy composites were characterized by SEM and confirmed the formation of the nanoparticles and nanorods on the modified electrode which leads to provide more surface area for the reductive elimination reaction. The elemental composition, functional groups and phase of materials on the modified electrode were deduced using EDX, Raman spectroscopy and XRD, respectively. Eu/ZnO/pPy/Au electrode was utilized for the photoelectrocatalytic degradation of SM as it exhibit excellent electrocatalytic activity and degradation products were analyzed by GC-MS. In the reductive elimination of SM, the following parameters were deduced (i) heterogeneous rate constant (0.127 s⁻¹), (ii) transfer coefficient (0.32) and (iii) number of electron involved (1.0). The enhanced photoelectrocatalytic capability of this nanocomposite could serve as a novel and promising catalyst in defence and environmental applications.

Mercury, a toxic trace metal, has been used extensively as an inexpensive and readily available method of extracting gold from fine-grained sediment. Worldwide, artisanal mining is responsible for one third of all mercury released into the environment. By testing bat hair from museum specimens and field collected samples from areas both impacted and unimpacted by artisanal gold mining in Perú, we show monomethylmercury (MMHg) has increased in the last 100 years. MMHg concentrations were also greatest in the highest bat trophic level (insectivores), and in areas experiencing extractive artisanal mining. Reproductive female bats had higher MMHg concentrations, and both juvenile and adult bats from mercury contaminated sites had more MMHg than those from uncontaminated sites. Bats have important ecological functions, providing vital ecosystem services such as pollination, seed dispersal, and insect control. Natural populations can act as environmental sentinels and offer the chance to expand our understanding of, and responses to, environmental and human health concerns.